METHOD OF FORMING SHALLOW TRENCH ISOLATION USING DEEP TRENCH ISOLATION
First Claim
1. A method of forming isolating regions of a semiconductor device, the method comprising:
- providing a workpiece, the workpiece having at least one first region and at least one second region, the workpiece having a top surface;
forming at least one first active area in said at least one first region;
patterning the first region with at least one first trench after said step of forming said first active area, the first trench having sidewalls, a bottom, and a first width and a first depth within the workpiece;
forming a first insulating layer over the at least one first trench sidewalls and bottom;
depositing a semiconductive material in the at least one first trench over the first insulating layer;
depositing a photo resist for patterning shallow second trenches over said first and second regions of said substrate;
patterning both said first and second regions each region patterned with at least one second trench, the second trench having a second depth within the workpiece, that is less than the first depth and a second width greater than said first width, said second trenches in said first region being located over said first trenches so as to recess said first insulating layer adding semiconductor material in said first trenches;
depositing an insulating material in the at least one second trench and in the semiconductive material recess of the at least one first trench; and
then forming at least one second active area in the second region.
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Accused Products
Abstract
A method of isolating active areas of a semiconductor workpiece. Deep trenches are formed in a workpiece between adjacent first active areas, and an insulating layer and a semiconductive material are deposited in the deep trenches. The semiconductive material is recessed below a top surface of the workpiece. Shallow trenches are formed in the workpiece between adjacent second active areas, and an insulating material is deposited in the shallow trenches and in the semiconductive material recess. The deep trenches may also be formed between an adjacent first active area and second active area. The first active areas may be high voltage devices, and the second active areas may be low voltage devices. The shallow trench isolation over the recessed semiconductive material in the deep trenches is self-aligned.
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Citations
26 Claims
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1. A method of forming isolating regions of a semiconductor device, the method comprising:
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providing a workpiece, the workpiece having at least one first region and at least one second region, the workpiece having a top surface;
forming at least one first active area in said at least one first region;
patterning the first region with at least one first trench after said step of forming said first active area, the first trench having sidewalls, a bottom, and a first width and a first depth within the workpiece;
forming a first insulating layer over the at least one first trench sidewalls and bottom;
depositing a semiconductive material in the at least one first trench over the first insulating layer;
depositing a photo resist for patterning shallow second trenches over said first and second regions of said substrate;
patterning both said first and second regions each region patterned with at least one second trench, the second trench having a second depth within the workpiece, that is less than the first depth and a second width greater than said first width, said second trenches in said first region being located over said first trenches so as to recess said first insulating layer adding semiconductor material in said first trenches;
depositing an insulating material in the at least one second trench and in the semiconductive material recess of the at least one first trench; and
then forming at least one second active area in the second region. - View Dependent Claims (2, 4, 5, 6)
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3. (Canceled)
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7. (Cancelled)
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8. (Cancelled)
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9. (Cancelled)
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10. A method of forming isolating regions of a semiconductor device, the method comprising:
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providing a workpiece, the workpiece having at least one first region and at least one second region, the workpiece having a top surface;
forming at least one high voltage active area in said at least one first region;
patterning the first region with at least one deep trench after forming said at least one high voltage active area, the deep trench having a first width, sidewalls, a bottom, and a first depth within the workpiece;
forming a first insulating layer over the at least one deep trench sidewalls and bottom;
depositing a semiconductive material in the at least one deep trench over the first insulating layer;
recessing said semiconductive material beneath the workpiece top surface;
forming a hard mask having portions over said at least one first region and over said at least one second region;
patterning the portion of said hard mask over said at least one second region and transferring said hard mask pattern to form at least one shallow trench in said second region and leaving the portion of said hard mask over said first region in place such that said first region is not further patterned, the shallow trench having a second depth and a second width within the workpiece, wherein the second depth is less than the first depth and the second width is greater than said first width;
removing any remaining hard mask from over at least one first region and said at least one second region;
depositing an insulating material in the at least one shallow trench and in the semiconductive material recess of the at least one deep trench; and
forming at least one low voltage active region in the second region. - View Dependent Claims (11, 12, 13, 14, 18, 19, 20, 21, 25, 26)
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15. (Cancelled)
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16. (Cancelled)
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17. (Cancelled)
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22. (Cancelled)
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23. (Cancelled)
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24. (Cancelled)
Specification